The list-style-type allows you to control the shape or appearance of the marker. You can try to run the following code to implement list-style-type property to work for the unordered list:
Example
<html> <head> </head> <body> <ul style = "list-style-type:circle;"> <li>Apple</li> <li>Mango</li> <li>Grapes</li> </ul> </body> </html>